Quick answers
- Does Mario J. Castellanos accept Medicare assignment?
- Yes. Medicare's clinician data says Mario J. Castellanos accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- What is Mario J. Castellanos's NPI number?
- 1164050910. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mario J. Castellanos works
Medicare's Facility Affiliation Data lists Mario J. Castellanos at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Brigham and Women Faulkner HospitalJamaica Plain, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220119
- Sage Memorial HospitalGanado, AZ · Critical Access Hospital · Emergency services: not listed by Medicare · CCN 031309
Practice locations
Addresses where Mario J. Castellanos is enrolled with Medicare (CMS data updated October 2, 2026).
- 75 Francis StBoston, MA 02115 (617) 732‑5500
Group practices
Medicare enrollment lists Mario J. Castellanos as a member of this group (CMS data updated October 2, 2026).
- Brigham and Womens Physicians Organization Inc2,994 clinicians in the group
Specialties
- Emergency Medicineprimary
Other emergency medicine doctors in Boston
Clinicians with the same Medicare primary specialty in Boston, MA — not a recommendation.
Other clinicians in Brigham and Womens Physicians Organization Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Medical College Of Wisconsin |
| Graduation year | 2021 (5 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1164050910 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians